Background

Following the Russian October Revolution of 1917, the new
Bolshevik government
signed a separate peace with Germany. The collapse of the Russian front
presented a tremendous problem to the Entente powers, since not only did it
allow Germany to shift troops and war material from its eastern
front to the west, but it also made it possible for Germany to
secure the huge stockpiles of supplies that had been accumulating
at Murmansk, Arkhangelsk and Vladivostok. In
addition, the 50,000 man Czech Legion, fighting
on the side of the Allies, was now trapped behind enemy-lines, and
was attempting to fight its way out through the east to Vladivostok
along the Bolshevik-held Trans-Siberian Railway.

Faced with these concerns, Great Britain and France decided to militarily intervene in the
Russian Civil War against the Bolshevik government. They had three
objectives that they hoped to achieve:

prevent the Allied war material stockpiles in Russia from
falling into German hands

Canada

The Canadian Siberian Expeditionary Force, commanded by Major
General James H. Elmsley and authorised in August 1918, was sent to
Vladivostok to bolster the allied presence there. Composed of 4,192
soldiers, the force returned to Canada between April and June 1919.
During this time, the Canadians saw little fighting, with fewer
than 100 troops proceeding "up country" to Omsk, to serve as
administrative staff for 1,500 British troops aiding the White
Russian government of Admiral Alexander Kolchak. Most Canadians
remained in Vladivostok, undertaking routine drill and policing
duties in the volatile port city.[2][3]

Italy

The "Corpo di Spedizione Italiano in Estremo Oriente" was made
of Alpini troops, supported by
2,500 ex-Italian POWs, who had fought in the Austro-hungarian Army,
enrolled in the Legione Redenta.

The Italians played a small but important role during the
intervention, fighting together with the Czechoslovak Legion and other
allied forces using heavily armed and armoured trains to control large
sections of the Siberian railway.[4]

Japan

A Japanese propaganda lithograph rallying for occupation of the
Russian Far East.

The Japanese were initially asked by the French in 1917, to
intervene in Russia but declined the request.[6]
However, the army general staff later came to view the Tsarist
collapse as an opportunity to free Japan from any future threat
from Russia by detaching Siberia and forming an independent buffer
state.[6]
The Japanese government in the beginning refused to undertake such
an expedition and it was not until the following year that events
were set in motion that led to a change in this policy.[6]

In July 1918, President Wilson asked the Japanese government to
supply 7,000 troops as part of an international coalition of 25,000
troops, including an American expeditionary
force, planned to support the rescue of the Czech Legion and
recurring of wartime supplies. After heated debate in the Diet, the
administration of Prime MinisterTerauchi
Masatake agreed to send 12,000 troops, but under the command of
Japan, rather than as part of an international coalition.

Once the political decision had been reached, the Imperial Japanese Army took over
full control under Chief of Staff Yui Mitsue and extensive planning for the
expedition was conducted.[7]

Although General Graves did not arrive in Siberia until
September 4, 1918, the first 3,000 American troops disembarked in
Vladivostok between August 15 and August 21, 1918. They were
quickly assigned guard duty along segments of the railway between
Vladivostok and Nikolsk-Ussuriski
in the north.[9]

Unlike his Allied counterparts, General Graves believed their
mission in Siberia was to provide protection for American-supplied
property and to help the Czechoslovak Legions evacuate
Russia, and that it did not include fighting against the
Bolsheviks. Repeatedly calling for restraint, Graves often clashed
with commanders of British, French and Japanese forces, who wanted the Americans to take
a more active part in the military intervention in Siberia.

Allied intervention
(1918-1919)

The joint Allied intervention began in August 1918.[7]
The Japanese entered through Vladivostok and points along the
Manchurian border with more than 70,000 Japanese troops being
involved. The deployment of a large force for a rescue expedition
made the Allies wary of Japanese intentions.[7]
On September 5, the Japanese linked up with the vanguard of the
Czech Legion.[7]
A few days later the British, Italian and French contingents joined
the Czechs in an effort to re-establish the east Front beyond the
Urals; as a result the European allies trekked westwards.[7]
The Japanese, with their own objectives in mind, refused to proceed
west of Lake Baikal[7]
and stayed behind. The Americans, suspicious of Japanese
intentions, also stayed behind to keep an eye on the Japanese.[7]
By November, the Japanese occupied all ports and major towns in the
Russian Maritime
Provinces and in Siberia
east of the city of Chita.[7]

In the summer of 1918 onwards, the Japanese army lent its
support to White Russian elements[7];
the 5th infantry
division and the Japanese-backed Special Manchurian Detachment
of Grigory Semyonov took control over Transbaikalia and
founded a short-lived White Transbaikalia
government.

Allied withdrawal
(1919-1920)

With the end of the war in Europe the allies decided to support
the anti-Bolshevik White forces and effectively intervene in the
Russian Civil War. Allied army support was given to Admiral
Kolchak's White government at Omsk
while the Japanese continued to support Kolchak's rivals in Grigory
Semyonov and Ivan Kalmykov.[10]
In the Summer of 1919, the White regime in Siberia collapsed,[10]
after the capture and execution of Admiral Kolchak by the Red Army.

In June 1920, the Americans, British and the remaining allied
coalition partners withdrew from Vladivostok. The evacuation of the Czech
Legion was also carried out in the same year. However, the Japanese
decided to stay, primarily due to fears of the spread of communism so close to
Japan, and the Japanese controlled Korea and Manchuria. The Japanese were forced to sign
the Gongota Agreement of 1920 in
order to evacuate their troops peacefully from Transbaikal. It
meant an unavoidable end to Grigory Semyonov's regime in October
1920.

The Japanese army provided military support to the
Japanese-backed Provisional Priamur Government based in
Vladivostok against the Moscow-backed Far Eastern Republic. The
continued Japanese presence concerned the United States, which
suspected that Japan had territorial designs on Siberia and the
Russian Far East. Subjected to intense diplomatic pressure by the
United States and Great Britain, and facing increasing domestic
opposition due to the economic and human cost, the administration
of Prime Minister Kato Tomosaburo
withdrew the Japanese forces in October 1922.

Legacy

Effects on Japanese
politics

Japan's motives in the Siberian Intervention were complex and
poorly articulated. Overtly, Japan (as with the United States and
the other international coalition forces) was in Siberia to
safeguard stockpiled military supplies and to "rescue" the Czech
Legion. However, the Japanese government's intense hostility to
communism, a determination to recoup historical losses to Russia,
and the perceived opportunity to settle the “northern problem” in
Japan's security by either creating a buffer state[6],
or through outright territorial acquisition, were also factors.
However, patronage of various White Movement leaders left Japan in
a poor diplomatic position vis-à-vis the government of the Soviet Union, after
the Red Army eventually emerged victorious from the Russian Civil
War. The intervention tore Japan's wartime unity to shreds, leading
to the army and government being involved in bitter controversy and
renewed faction strife in the army itself.[6]

Japanese casualties from the Siberian Expedition included some
5,000 dead from combat or illness, and the expenses incurred were
in excess of 900 million yen.